Who do I ask for a reference after a layoff? after 8 years as a bank teller

The company closed and I am not sure how to reach former colleagues. Any experience at all would help. A colleague offered to vouch for me. How do you ask politely?

Ask former colleagues and supervisors in a short message and give them a summary of the job you are applying for.

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.